Bacterial microenvironment-responsive antibacterial, adhesive, and injectable oxidized dextran-based hydrogel for chronic diabetic wound healing.

Diabetic wounds are highly susceptible to bacterial infections, often resulting in chronic wounds that pose a substantial challenge to clinical treatment. Furthermore, the irregular shapes of these wounds limit the effectiveness of conventional dressings. Therefore, development of a new type of antibacterial dressing that can accommodate various wound shapes is urgently required. In this study, we designed injectable hydrogels with bacterial microenvironment-responsive antibacterial, adhesive, and antioxidant properties. These hydrogels were developed by incorporating polydopamine nanoparticles (PDA NPs) into a gelatin/oxidized dextran (Gel-oDex) network crosslinked via dynamic Schiff base reactions. Notably, the Gel-oDex-PDA-PHMB hydrogel demonstrated strong antibacterial efficacy against S. aureus, E. coli, and MRSA (all exceeding 99%), with PHMB-release experiments confirming its responsiveness to the bacterial microenvironment. Additionally, the hydrogel exhibited significant antioxidant activity, as evidenced by the DPPH radical scavenging assays. With good biocompatibility, the Gel-oDex-PDA-PHMB hydrogel also demonstrated effectiveness in killing bacteria and promoting the regeneration and functional reconstruction of skin tissue in bacteria-infected diabetic rats.